Ritt U.S. Pat. No. 4,763,102 discloses a cartridge heater with a resistance wire heating element wound on a flat, rectangular core of insulating material as a mica splitting or mica paper. The heating element is fitted in a cylindrical sheath which may, for example, be of stainless steel or brass. The heating element and core are positioned in the sheath by bushings or centralizers at either end. The ends of the core are received in complimentary opposed slots in the bushings. The sheath is filled with a granular insulating material as magnesium oxide.
This application is concerned with an improved heater assembly for a swaged cartridge heater and with the method of manufacture of the heater assembly. The granular insulation of a swaged cartridge heater is compacted, affording a higher wattage and temperature rating for the heater.